A grain transfer control system, and method of use thereof, for automatedly controlling the transfer of grain from a mobile transferor-type vehicle (CH1), such as a combine harvester, to a mobile transferee-type vehicle (GT1), such as a crop transport, by varying the position and speed of the transferor-type and transferee-type vehicle (GT1 )s relative to one another during the transfer operation, especially by varying the position and rate of walk of the discharge spout (62) along at least a portion of the length of a grain holding receptacle (70) of the transferee-type vehicle (GT1), to effect a generally even fill of the grain holding receptacle (70) of the transferee-type vehicle (GT1) along the length of the grain holding receptacle (70).
